Persico tests PA and PC materials for rotomoulding
Italian company Persico has been working with new rotomoulding materials to help processors diversify from their reliance on PE. It has developed a PA6 material in which the raw materials - caprolactam plus activator and caprolactam plus catalyst - are melted and blended in two separate tanks and then brought together in a mixing chamber. They are then charged into rotating moulds heated to the proper temperature for polymerisation. The solidification of the material occurs through a chemical reaction, not by cooling inside the mould. Mould charging with the raw material is done in multiple stages. Precise monitoring and control of the mould temperatures are achieveable in Persico's automated Leonardo rotomoulding machine. Its heating elements are a series of resistors applied directly on the mould surface. The company has also been moulding transparent PC, which requires precise mould temperature control and a rotation speed higher than in traditional rotational moulding. Polycarbonate moulding generates air bubbles that affect the mechanical properties of the material, as well as its aesthetic appearance. Persico found in tests that a vacuum technique led to the complete removal of the bubbles.